While she said she wasn’t aware that the venue will close after reaching capacity, Donnelly unwittingly embodied the single piece of advice Vail Resorts’ director of marketing and sales said he can’t stress enough.

“It’s not unlimited capacity,” David Ratchford said on Thursday. “We want as many people there as possible, obviously, but we need people to understand that the venue doors will open, and we will, at some point, have to shut that down ... if we get to 7,500 people, 8,000 people ... we’ll close the doors and people will just need to understand that.”

Ratchford said he expects tonight’s show to reach capacity fairly quickly.

“Sound Tribe Sector 9, STS9, that’s going to be huge,” he said. “These guys have sold out huge concerts in the past. They’re a really popular group, and if people are thinking, ‘Yeah, we’ll get over there about 8 o’clock,’ they’ll be disappointed.”

BACK TO Two WEEKENDS

This year, Spring Back to Vail spans across two weekends.

In addition to the Dirty Dozen Brass Band and Karl Denson’s Tiny Universe on Friday night, and The Polish Ambassador and STS9 tonight, there’s another free concert Sunday — all female Led Zeppelin cover band Lez Zeppelin — and Steel Pulse plays next Sunday, April 20, with opener Bonfire Dub.

Vail hires Highline Sports and Entertainment to produce Spring Back to Vail, and James Deighan with Highline says Ratchford’s idea to run Spring Back to Vail across two weekends this season was a stroke of genius.

“It used to be two weekends, and with the way Easter fell this year, I think it was the right move to bring it back to that format again,” Deighan said Friday.

For veterans like Deighan, the true lure to Spring Back to Vail doesn’t lie in the free concerts.

Of the 150-plus events Highline produces every year, Deighan says Spring Back to Vail’s World Pond Skimming Championships — scheduled for 3 p.m. April 20, is his personal favorite.

“Every year it’s just such a blast, I have so many fond memories,” Deighan said. “I remember about 10 years ago, a few guys came down and laid down a huge, smackdown belly flop into the pond that totally drenched the first 20 rows of the crowd, and I turned over to look at (now Vail’s Chief Operating Officer) Chris Jarnot, who was officiating at the time, and he was just doubled over crying he was laughing so hard. That pretty much sums up this event.”

TEST YEAR

Ratchford says this year could serve as a test scenario for a return to the two-weekend format for Spring Back to Vail.

“I think we’re definitely experimenting to see — can we spread this out?” he said. “The feedback that we have right now is that next week is going to be a pretty good week for us; there’s going to be a lot of people here enjoying Easter and enjoying their time off.”

Ratchford says in Vail Resorts’ experience, how you end one season sets up how you begin the next.

“It means a lot to people,” he said.

As far as the future, Ratchford says he’d like to experiment with a youth pond skimming event.

“I think that’d be something fun for us to look at in the future,” he said. “I know my kids are waiting until they’re of age to do pond skimming ... I would say there’s a really good opportunity for that in the future. I’ve seen it done before, out in Tahoe at Northstar.”

Ratchford’s kids are ages 11, 9, 7 and 3. He says in addition to the pond skimming, their other favorite activity at Spring Back to Vail is combing the sponsor village for free swag.

“Kids have a great time at these things, these partner villages where we have folks give away free things or play free games, those things are super fun for families.”